Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the mutation profile (readOnlyHint false, idempotentHint true, destructiveHint false), so the description's job is to add context. It clarifies that endorsement is additive rather than a new request and that the price is optional, but says nothing about what happens on re-endorsement, whether an endorsement can be withdrawn, or whether it affects the demand's existing price.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the action and immediately followed by the sibling routing rule. No redundant restatement of the title.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The core action and the sibling choice are covered, and annotations carry the safety profile, but for a mutation tool with five parameters, no output schema, and only 20% schema coverage, the missing meaning for currency and expected_monthly_units leaves real gaps an agent must guess at.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 20%, and the description compensates only partially by hinting at "your own price" (max_price/price_unit). currency and expected_monthly_units are left with no explanation anywhere, including what unit basis or magnitude the agent should supply.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

"Add your support (and optionally your own price) to an existing request" names the verb (endorse) and the exact resource (an existing demand), and the reference to browse_demand makes it distinct from register_demand without needing the schemas opened.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Prefer this over registering a duplicate" gives a clear routing rule against the register_demand sibling, and "existing request from browse_demand" tells the agent where the demand_id comes from. There is no explicit when-not case (e.g., what to do if no matching demand exists), so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.